Modular tapered reamer for bone preparation and associated method

ABSTRACT

A kit ( 400 ) for use in performing joint arthroplasty is provided. The kit ( 400 ) includes a trial ( 12 ) and a reamer ( 2 ). The reamer ( 2 ) is for preparing a cavity ( 4 ) in the intramedullary canal ( 8 ) of a long bone ( 8 ) with the use of a driver ( 10 ) and to assist in performing a trial reduction. The reamer ( 2 ) includes a first portion ( 14 ) for placement at least partially in the cavity ( 4 ) of the long bone ( 8 ) and a second portion ( 16 ) operably connected to the first portion ( 14 ). The reamer ( 2 ) is removably connected to the driver ( 10 ) to rotate the reamer ( 2 ). The trial ( 12 ) is removably attachable to the reamer ( 2 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

Cross reference is made to the following applications: DEP 670 entitled“ASSEMBLY TOOL FOR MODULAR IMPLANTS AND ASSOCIATED METHOD” and DEP 5083entitled “NON-LINEAR REAMER FOR BONE PREPARATION AND ASSOCIATED METHOD”filed concurrently herewith which are incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to the field of orthopaedics,and more particularly, to an implant for use in arthroplasty.

BACKGROUND OF THE INVENTION

Patients who suffer from the pain and immobility caused byosteoarthritis and rheumatoid arthritis have an option of jointreplacement surgery. Joint replacement surgery is quite common andenables many individuals to function properly when it would not beotherwise possible to do so. Artificial joints are usually comprised ofmetal, ceramic and/or plastic components that are fixed to existingbone.

Such joint replacement surgery is otherwise known as joint arthroplasty.Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged joint is replaced with a prosthetic joint. In atypical total joint arthroplasty, the ends or distal portions of thebones adjacent to the joint are resected or a portion of the distal partof the bone is removed and the artificial joint is secured thereto.

There are known to exist many designs and methods for manufacturingimplantable articles, such as bone prostheses. Such bone prosthesesinclude components of artificial joints such as elbows, hips, knees andshoulders.

Currently in total hip arthroplasty, a major critical concern is theinstability of the joint. Instability is associated with dislocation.Dislocation is particularly a problem in total hip arthroplasty.

Factors related to dislocation include surgical technique, implantdesign, implant positioning and patient related factors. In total hiparthroplasty, implant systems address this concern by offering a seriesof products with a range of lateral offsets, neck offsets, head offsetsand leg lengths. The combination of these four factors affects thelaxity of the soft tissue. By optimizing the biomechanics, the surgeoncan provide a patient a stable hip much more resistant to dislocation.In order to accommodate the range of patient arthropometrics, a widerange of hip implant geometries are currently manufactured by DePuyOrthopaedics, Inc., the assignee of the current application, and byother companies. In particular, the S-ROM® total hip systems offered byDePuy Orthopaedics, Inc. include three offsets, three neck lengths, fourhead lengths and one leg length adjustment. The combination of all thesebiomechanic options is rather complex.

Anteversion of a total hip system is closely linked to the stability ofthe joint. Improper version can lead to abnormal biodynamics,dislocation and patient dissatisfaction. Version control is important inall hip stems. However, it is a more challenging issue with the adventof stems with additional modularity.

The prior art has provided for some addressing of the anteversionproblem. For example, the current S-ROM® stems have laser markings onthe medial stem and the proximal sleeve. This marking enables thesurgeon to measure relative alignment between these components. Sincethe sleeve has infinite anteversion, it is not necessarily orientedrelative to a bony landmark that can be used to define anteversion. Infact, the current sleeves are sometimes oriented with the spout pointingdirectly laterally into the remaining available bone.

Prior art stems may be aligned relative to a patient's bony landmarks.These stems are monolithic. They cannot locate the neck independently ofthe distal stem. Therefore, the anteversion is limited. Most bowed,monolithic stems are sold in fixed anteversion; for example, at ananteversion of 15 degrees. These monolithic stems have limitedflexibility for rotational alignment since the distal stem must followthe bow of the patient's femur and this may not provide an operablebiomechanical result.

When a primary or index total joint arthroplasty fails, a revisionprocedure is performed in which the index devices (some or all) areremoved. Quite often the remaining bone is significantly compromisedcompared to a primary hip procedure. Significant bone loss is observed,often with a lack of bone landmarks typically used for alignment.

In a common step in the surgical procedure known as total hiparthroplasty, a trial or substitute stem is first implanted into thepatient. The trial is utilized to verify the selected size and shape ofthe implant in situ on the patient and the patient is subjected to whatis known as a trial reduction. This trial reduction represents movingthe joint, including the trial implant through selected typical motionsfor that joint. Current hip instruments provide a series of trials ofdifferent sizes to help the surgeon assess the fit and position of theimplant. Trials, which are also known as provisionals, allow the surgeonto perform a trial reduction to assess the suitability of the implantand implant's stability prior to final implant selection. The trial alsoduplicates the implant's geometry. In order to reduce inventory costsand complexity, many trialing systems are modular. For example, in theExcel™ Instrument System, a product of DePuy Orthopaedics, Inc., thereis a series of broaches and a series of neck trials that can be mixedand matched to represent the full range of implants. There is a singlefixed relationship between a broach and a neck trial, because thesetrials represent a system of monolithic stem implants.

Likewise, in the current S-ROM® instrument systems provided by DePuyOrthopaedics, Inc., there are neck trials, proximal body trials, distalstem trials, head trials and sleeve trials. By combining all of thesecomponents, the implant is represented. Since the S-ROM® stem is modularand includes a stem and a sleeve, the angular relationship or relativeanteversion between the neck and the sleeve is independent andrepresented by teeth mating between the neck and the proximal bodytrial. The proximal body trial has fixed transverse bolts that are keyedto the sleeve in the trialing for straight, primary stems. The long stemtrials do not have the transverse bolts and are thus not rotationallystable during trial reduction and therefore are not always used by thesurgeon.

With the introduction of additional implant modularity, the need forindependent positioning of the distal stem, proximal body and any sleevewhich comprise the implants is required. Currently bowed, monolithicstems are offered with a fixed amount of anteversion, typically 15degrees.

When performing joint arthroplasty, the long bone is resected and thecavity is prepared for the prosthetic stem. The canal is prepared by,for example, reamers, for example, a tapered reamer. After the canal hasbeen reamed, a trial prosthesis is positioned in the cavity. A trialreduction is then performed with that trial. If the trial reduction issuccessful, the trial is removed and an implant corresponding to thattrial is placed in the cavity. Each step of the process, for example,the positioning of the trial after the reaming and the positioning ofthe implant after the trialing provides for an additional location errorin the proper placement of the prosthesis, as well as additional timefor the surgical procedure. There thus remains a need for improving thepositioning of a prosthesis while reducing the surgical time in whichthe patient is at risk.

U.S. patent application Ser. No. 10/327,187 entitled “ADJUSTABLEBIOMECHANICAL TEMPLATING & RESECTION INSTRUMENT AND ASSOCIATED METHOD”,U.S. patent application Ser. No. 10/327,196 entitled “ALIGNMENT DEVICEFOR MODULAR IMPLANTS AND METHOD” and U.S. patent application Ser. No.10/327,527 entitled “INSTRUMENT AND ASSOCIATED METHOD OF TRIALING FORMODULAR HIP STEMS” are hereby incorporated in their entireties byreference.

SUMMARY OF THE INVENTION

The applicants have found that the surgeon will have the greatestcertainty that the trial reduction biomechanics are correct if thesurgeon can do the trial reduction with the reamer still in position inthe canal. Systems in use today, however, require the user to remove thereamer and insert a trial stem to do a trial reduction. A trialreduction from the reamer ensures that the relative references aremaintained. The applicants have determined that to permit the trialreduction off the reamer, the proximal attachment linking the reamer tothe power source may be modular. The drive shaft for the reamer shouldpreferably be long enough to reach outside of the patient. Theapplicants have been able to overcome the problem that a femoral triallong enough to work with the drive shaft will affect the biomechanics ofthe trial reduction.

The applicants have discovered that by providing a modular connectionfor which the driver may be modularly connected to the cutting edge ofthe reamer, the distal or cutting edge portion of the reamer may beseparated from the driver while the reamer is still in position in thepatient. A proximal trial portion may then be placed on the in-positionreamer located in the femoral canal. The distal reamer and the proximaltrial may then be used as a trial to perform a trial reduction on thepatient. The use of the combination of a proximal reamer and distaltrial provides for a reduction in the steps necessary to go from reamingto the implant, thus improving the positioning of the final implant. Thepositioning of a proximal trial on a distal reamer also reduces thesteps necessary in performing an arthroplasty and reduces the amount oftime the patient is under the anesthesia.

According to one embodiment of the present invention, there is provideda kit for use in performing joint arthroplasty. The kit includes a trialand a reamer. The reamer is for preparing a cavity in the intramedullarycanal of a long bone with the use of a driver and to assist inperforming a trial reduction. The reamer includes a first portion forplacement at least partially in the cavity of the long bone and a secondportion operably connected to the first portion. The reamer is removablyconnected to the driver to rotate the reamer. The trial is removablyattachable to the reamer.

According to another embodiment of the present invention there isprovided a kit for use in performing hip joint arthroplasty, the kit isused to prepare a cavity in the femoral canal of a femur with the use ofa driver. The kit is also used to assist in performing a trialreduction. The kit includes a hip femoral component trial and a reamer.The reamer is used for preparation of the cavity in the femoral canal.The reamer includes a first portion for placement at least partially inthe cavity of the femur and a second portion connectable to the driver.The trial and the driver are removably attachable to the reamer, so thatthe reamer and the driver can be assembled to prepare the cavity and sothat the reamer and the trial can be assembled to form a hip femoralcomponent trial assembly without the removal of the reamer from thecavity.

According to yet another embodiment of the present invention there isprovided a reamer for preparing a cavity in the intramedullary canal ofa long bone with the use of a driver and for cooperation with an implanttrial to assist in performing a trial reduction. The reamer includes afirst portion for preparation of the cavity in the canal. The firstportion is adapted for placement at least partially in the cavity of thelong bone. The reamer also includes a second portion operably connectedto the first portion. The second portion is connectable to the driver torotate the reamer. The reamer is removably attachable to the trial andto the driver.

According to a further embodiment of the present invention, there isprovided a method for providing joint arthroplasty. The method includesthe steps of resecting a long bone, opening a medullary canal of thelong bone, providing a reamer including a surface for the removal ofbone, attaching a driver to the reamer, positioning the reamer in thecanal, reaming a cavity in the canal with the reamer, detaching thedriver from the reamer, providing a trial, attaching the trial to thereamer, and performing a trial reduction.

The technical advantages of the present invention include the reductionof dislocations by improving the stability of the joint. For example,according to one aspect of the present invention, a proximal trial isplaced on a reamer which remains in the canal after the reaming has beenperformed. The trialing can thus be performed from the reamer. The addedstep of removing the reamer and placing the trial in the hole preparedby the reamer is eliminated and the resultant reduction inaccuracy ofthe position of the trial is thereby eliminated. Thus, the positioningof the trial with respect to the reamed cavity is improved. Because ofthe improved positioning of the trial, the stability of the joint isimproved and dislocation is reduced. Thus, the present inventionprovides for improved stability and positioning of the joint.

Another technical advantage of the present invention includes theability of the modular reamer of the present invention to provideoptimal biomechanics. Because of the shallow taper angle, axialpositioning is difficult. The present invention provides for improvedpositioning of the prosthesis and an optimization of the soft tissueposition and the reduction of soft tissue laxity. For example, accordingto one aspect of the present invention, the modular reamer permits themounting of a proximal trial on the reamer while the tapered reamer isstill in position in the canal. The surgeon has the greater certaintythat the trial reduction biomechanics are correct if he can do the trialreduction off the reamer. This ensures that the relative references aremaintained. By eliminating the additional step of removing the reamerand implanting a distal trial as well as the proximal trial, theaccuracy of the trial and resultant implant positioning is improved. Theimproved positioning of the prosthesis provides for improved soft tissuepositioning and optimum biomechanics. Thus, the present inventionprovides for optimum biomechanics.

Another technical advantage of the present invention includes improvedanteversion or the angular orientation of the joint in the body. Forexample, according to another aspect of the present invention, thedriver may be separated from the distal reamer while the distal reameris still in position in the bone canal and a proximal trial may bepositioned on the reamer. The trialing of the prosthesis on the reamerallows for relative rotational position and provides for improvedaccuracy of the positioning of the trial and therefore improvedanteversion of the joint in the body. Thus, the present inventionprovides for improved anteversion of the joint in the body.

Yet another technical advantage of the present invention includes areduction in the surgery time, which reduces the time the patient is atrisk for surgery related complications. For example, according to oneaspect of the present invention, the driver may be removed from thedistal reamer while the distal reamer is still in position in the canaland a proximal trial may be positioned on the distal reamer. Theprosthesis may thus be trialed off the reamer. Thus, the additional stepof removing the reamer and positioning a distal trial in the cavity iseliminated thereby reducing the steps necessary for the procedure andthe corresponding additional time for the removal of the reamer and theplacement of the distal trial. Thus, the present invention provides forreduced surgery time and reduced patient complications during surgery.

Yet another technical advantage of the present invention includes theability to use the medullary canal of the long bone or femur as areference for the proper positioning of the implant, particularly when arevision procedure is performed in which the normal bone are landmarks,such as the greater and lesser trochanter, (some or all) are no longerpresent. For example, according to one aspect of the present invention,a proximal trial is placed on a reamer which is used to ream themedullary canal of the long bone or femur. The reamer remains in thecanal after the reaming has been performed. The trialing can thus beperformed from the reamer. Thus, the present invention provides for theuse of the medullary canal of the long bone or femur as a reference forthe proper positioning of the implant.

By being able to trial off the reamers, one can eliminate a whole trayof instruments which reduces cost and system complexity.

Other technical advantages of the present invention will be readilyapparent to one skilled in the art from the following figures,descriptions and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptiontaken in connection with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a modular reamer assembly inaccordance with an embodiment of the present invention and a plan viewof a trial for use with the modular reamer;

FIG. 2 is a cross sectional view of the modular reamer assembly of FIG.1;

FIG. 3 is a plan view of the modular reamer assembly of FIG. 1;

FIG. 4 is a partial plan view of the modular reamer assembly of FIG. 1showing the proximal end in greater detail;

FIG. 5 is a partial cross sectional view of the modular reamer holder ofthe modular reamer assembly of FIG. 1;

FIG. 6 is a plan view of the modular reamer of the reamer assembly ofFIG. 1;

FIG. 7 is a bottom view of the modular reamer of FIG. 6;

FIG. 8 is a plan view partially in cross-section of the modular reamerof FIG. 6 in position in the medullary canal of a femur;

FIG. 9 is a plan view of a hip stem trail mounted on the modular reamerof FIG. 6 shown in position in the medullary canal of a femur preparedby the modular reamer assembly of FIG. 9;

FIG. 10 is a plan view of the hip stem trail and modular reamer assemblyof FIG. 9;

FIG. 11 is a top view of the hip stem trail and modular reamer assemblyof FIG. 10;

FIG. 12 is a plan view of the hip stem trail of the modular reamerassembly of FIG. 10;

FIG. 13 is a top view of the hip stem trail of FIG. 12;

FIG. 14 is a top view of a nut for use with the modular reamer assemblyof FIG. 9;

FIG. 15 is a plan view of the nut for use with the modular reamerassembly of FIG. 9;

FIG. 16 is a plan view of the modular reamer of FIG. 6 with the hip stemtrial of FIG. 12 shown in phantom;

FIG. 17 is a plan view of an adaptor for use with the modular reamer ofFIG. 6 and with the hip stem trial of FIG. 12;

FIG. 18 is a top view of the adaptor of FIG. 17;

FIG. 19 is a plan view of another embodiment of a modular reameraccording to the present invention with a tapered shank and without athreaded proximal end;

FIG. 20 is a plan view of another embodiment of a modular reameraccording to the present invention with a tapered shank and with athreaded proximal end;

FIG. 21 is a plan view of a proximal reamer for use with the modularreamer of FIG. 6 to provide clearance for the hip stem trial of FIG. 12;

FIG. 22 is a plan view of a proximal reamer of FIG. 21 shown in positionon the modular reamer of FIG. 6;

FIG. 23 is a cross sectional exploded view of the modular reamerassembly of FIG. 1 and a plan view of the trial of FIG. 12;

FIG. 24 is a plan view of another embodiment of the present invention inthe form of a kit including the modular reamer of FIG. 6, the driver ofFIG. 6, the hip stem trial of FIG. 12, the proximal reamer of FIG. 21,and an additional trial;

FIG. 25 is a perspective view of an alignment tool for use in aligningthe components of an implant to correspond to those of the hip stemtrail with the proximal portion of the hip stem trail and modular reamerassembly of FIG. 8 shown in phantom;

FIG. 26 is a plan view of an embodiment of a modular hip stem for use inthe medullary canal of a femur prepared by the modular reamer assemblyof FIG. 1;

FIG. 27 is an exploded plan view of the modular hip stem of FIG. 26;

FIG. 28 is a plan view partially in cross section of the modular hipstem of FIG. 26;

FIG. 29 is a partial perspective view of the threaded end of the modularhip stem of FIG. 26;

FIG. 30 is a partial top view of the threaded end of the prosthesis ofthe modular hip stem of FIG. 26;

FIG. 31 is a perspective view of the alignment tool of FIG. 25 shown inuse for aligning the stem of FIG. 26 to correspond to the alignment ofthe trial assembly of FIG. 10 shown with the hip stem in position;

FIG. 32 is a perspective view of an assembly tool shown in use forassembling the stem of FIG. 26;

FIG. 33 is a plan view of a second embodiment of a modular hip stemimplant;

FIG. 34 is an exploded plan view of the modular hip stem implant of FIG.33;

FIG. 35 is a flow chart of a surgical procedure according to the presentinvention utilizing a modular reamer;

FIG. 36 is a top view of an tool for use to tighten the nut of FIG. 15;and

FIG. 37 is a plan view of the tool of FIG. 36.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention and the advantages thereof are bestunderstood by referring to the following descriptions and drawings,wherein like numerals are used for like and corresponding parts of thedrawings.

Referring now to FIG. 1, a reamer 2 according to the present inventionis shown. The reamer 2 is utilized for preparing a cavity 4 in theintramedullary canal 6 of a long bone 8 with the use of a driver 10. Thereamer 2 cooperates with an implant trial 12 to assist in performing atrial reduction. The reamer 2 includes a first portion 14 forpreparation of the cavity 4 in the canal 6. The first portion 14 isadapted for placement at least partially in the cavity 4 of the longbone 8. The reamer 2 further includes a second portion 16 operablyconnected to the first portion 14. The second portion 16 is alsoconnectable to the driver 10 to rotate the reamer 2. The reamer 2 isremovably attachable to the trial 12 and to the driver 10.

As shown in FIG. 1, the first portion 14 of the reamer 2 may define alongitudinal axis 18 of the first portion 14. Similarly, the secondportion 16 of the reamer 2 may define a longitudinal axis 20 of thesecond portion 16. Longitudinal axis 20 of the second portion 16 may becoincident with the longitudinal axis 18 of the first portion 14. Asshown in FIG. 1, the reamer 2 may be separable and connectable to thedriver 10 and to the trial 12 along the longitudinal axis 18 of thefirst portion 14.

As shown in FIG. 1, the first portion 14 of the reamer 2 may include atapered external periphery 22. The tapered external periphery 22 isutilized to prepare a tapered cavity 4 in the canal 6. The secondportion 16 of the reamer 2 includes an external periphery 24. Theexternal periphery 24 may mate with, for example, an internal periphery26 formed on the driver 10.

The external periphery 24 of the second portion 16 of the reamer 2 is,as shown, cylindrical. It shall be appreciated that the externalperiphery 24 may be tapered. If periphery 24 is tapered then internalperiphery 26 of driver 10 would be likewise tapered.

If the external periphery 4 of the second portion 16 of the reamer 2 istapered, the taper may assist in providing a secure fit between thereamer 2 and either the driver 10 or the trial 12. The connectionresults in a very small outside diameter of the distal end of driveshaft 10, so that device can be used on small sizes.

Referring again to FIG. 1, the reamer 2 may further include a lockingfeature 28 adapted to lock the trial 12 and the driver 10 to the reamer2.

As shown in FIG. 1, the periphery 22 of the first portion 14 of thereamer 2 may be defined by an included angle α. The angle α may be anyangle conforming to the angle of the distal stem of the prosthetic andany suitable angle capable of providing secure engagement of theprosthesis.

If the external periphery of the second portion (not shown) of thereamer is tapered, the periphery may be defined by an included angle(not shown). The angle may be any suitable angle capable of providing asecure fit between the reamer and either of the driver or the trial.

While the reamer 2 of the present invention may be well suited toprepare the cavity of any long bone 8, the reamer 2 is particularly wellsuited for use in a femur. When the long bone 8 is in the form of afemur, the implant trial 12 will be in form of a hip femoral implanttrial.

Referring now to FIGS. 2 and 3, the reamer 2 is shown assembled onto thedriver 10. The reamer and driver 10 form reamer driver assembly 30. Thedriver 10 includes a connector 11 for connecting to a driving device(not shown) that may be manual or powered.

Referring now to FIG. 4, the locking feature 28 of the reamer 2 is shownin greater detail. The locking feature 28 may be any feature capable ofcooperating with either the driver 10 or the trial 12. For example, andas shown in FIG. 4, the locking feature 28 may include a void in theform of an axial slot 32 extending axially from end 34 of the reamer 2.

As shown in FIG. 4, the locking feature 28 may further include a bayonetor J channel 36 formed in periphery 24 of the second portion 16 of thereamer 2. It should be appreciated that additional locking features orconnecting features 28 may be provided. For example, as shown in FIG. 4,the locking feature 28 further includes opposed flats 38 formed on shank40 extending from proximal end 42 of the second portion 16 of the reamer2. The flats 38 are used primarily for alignment.

As shown in FIG. 4, the locking feature 28 may further include a ridge44 extending from the shank 40. The locking feature 28 may furtherinclude external threads 46 extending outwardly from the ridge 44 of theshank 40.

Referring now to FIG. 5, the driver 10 is shown in greater detail. Asshown in FIG. 5, the driver 10 includes a stem 48 to which a sleeve 50is slidably fitted. A spring 52 is fitted in a central end opening 54 ofthe stem 48. Spring 52 is retained by spring retaining pin 56 operablyconnected to the sleeve 50. The spring 52 is utilized to urge the sleeve50 in the direction of arrow 58 with respect to the stem 48.

A transverse cross-drive pin 60 is secured to the sleeve 50 and iscontained within an elongated slot 62 in the stem 48. The drive pin 60and the slot 62 serve to limit the relative motion of the sleeve 50 withrespect to the stem 48. Internal pins 64 extend inwardly from hollowportion 65 of stem 48.

Referring now to FIG. 5 and FIG. 4, the reamer 2 is inserted into thedriver 10 by aligning the periphery 24 of the second portion 16 of thereamer 2 into the hollow portion 65 of the stem 48. The internal pins 64are aligned with the bayonet or J channel 36 and the reamer 2 isadvanced in the direction of arrow 66.

By advancing the reamer 2 in the direction of arrow 66 the engagement ofthe end 34 of reamer 2 with the cross-drive pin 60 advances thecross-drive pin in the direction of arrow 68 until the spring 52 of thedriver 10 is partially collapsed and the internal pins 64 contact distalsurface 69 of the J-channel permitting the pins 64 to engage with secondportion 70 of the bayonet or J-channel 36. The reamer 2 is thus rotatedin the direction of arrow 72 until the cross-drive pin 60 is alignedwith the axial slot 32 and the engagement is complete.

Referring now to FIG. 6, the first portion 14 of the reamer 2 is shownin greater detail. As shown in FIG. 6, the reamer 2 may have a taperedgeometry. For example, the periphery 22 of the reamer 2 may form theincluded angle α. The angle α may be for example 0 to 20 degrees.

As shown in FIG. 6, the reamer 2 may include a plurality of flutes 74.The flutes 74 may extend in a straight axial direction as shown in FIG.6. It should be appreciated that the flutes 74 may alternatively bespiraled or skewed with respect to the longitudinal axis 18 of the firstportion 14. It should be appreciated that any number of flutes 74 may beutilized by the reamer 2.

As shown in FIGS. 6 and 7, the reamer 2 is shown with six (6) flutes.Each of the flutes 74 includes a cutting edge 76. A land 78 may bepositioned close to the cutting edge 76 to stabilize the reamer 2 as itis cutting. Reliefs 41 may be positioned between adjacent lands 78. Thereliefs 41 serve to provide a path for the removal and a location forcollection of bone chips and other debris. As shown in FIG. 6, thereamer 2 may also include a plurality of grooves 43. The grooves 43 asshown in FIG. 6 may form a spiral pattern with respect to the firstportion 14. The grooves 43 are used to help break up chips.

The reamer 2 may be made of any suitable durable material and may bemade of, for example, a metal. The reamer is preferably made of amaterial that may be sterilized by a conventional sterilizationtechnique such as by an autoclave. For example, the reamer 2 may be madeof a cobalt chromium alloy, a stainless steel alloy, or any otherdurable metal or other cutting tool material. It should be appreciatedthat the reamer 2 may be integral or be made of multiple pieces or amodular construction.

The components of the driver 10 may be made of any suitable durablematerial and be made of, for example, a plastic or a metal. For example,if the driver 10 is made of a metal, it is preferably made of asterilizable metal and may, for example, be made of a cobalt chromiumalloy, a titanium alloy, or a stainless steel alloy. The driver 10 mayalso be made of any suitable durable steel which may be sterilized bystandard methods, for example, by an autoclave.

Referring now to FIG. 8, the reamer 2 is shown in position on long boneor femur 8. The first portion 14 is shown in position in the canal 6 ofcavity 4 of the femur 8. As shown in FIG. 8, the locking feature 28 andthe proximal or second portion 16 may be positioned below the resectionline 45.

Referring now to FIG. 9, the trial 12 is shown installed on the reamer 2while the reamer 2 is still in position in the cavity 4 of the canal 6of the femur 8. Trial 12 is positioned in an anatomically correctposition with respect to the resection line 45.

Referring now to FIG. 10, the trial 12 is shown in position assembled toreamer 2. The trial 12 is attached at second portion 16 of the reamer 2.As shown in FIG. 10, the trial 12 may have a trial longitudinalcenterline 47 that is coincident with the centerline 20 of the secondportion 16 of the reamer 2 as well as coincident with the centerline 18of the first portion 14 of the reamer 2. It should be appreciated thatany one of a series of proximal trials may be used with differentdimensions such as offset height, calcar height etc.

Referring now to FIG. 11, the trial 12 is shown in greater detail. Asshown in FIG. 11, the trial 12 includes a proximal body 80 and a nut 82that is used to secure the proximal body 80 to the reamer 2. Theproximal body 80 includes a neck 84 from which extends an external taper86 for receiving the head (not shown) of the trial. The nut 82 issecured to the external threads 46 of the reamer 2 by internal threads88 formed on the nut 82. A knurl 90 on the periphery of the nut 82 areused to provide additional grip to assist in securing the nut 82 to thereamer 2.

Referring now to FIGS. 12 and 13, the proximal body 80 is shown ingreater detail. As shown in FIGS. 12 and 13, the body 80 defines athrough opening 90 for receiving the nut 82. The through opening 90 andthe body 80 define lips 92 for containing retaining spring 94. Retainingspring 94 cooperates with the ridge 44 of the head 40 of the reamer 2(see FIG. 4) to provide a connecting feature for snapping the body 80into position on the reamer 2.

Referring now to FIGS. 14 and 15, the nut 82 is shown in greater detail.Axial slots 96 extend inwardly from end 97 of the nut 82. The slots 96serve to provide a drive feature for properly torquing the nut 82 to thereamer 2. The nut 82 has an outer periphery 98 which is matingly fittedwith the through opening 90 to permit the nut 82 to fit within theopening 90 of body 80 of trial 12 (see FIG. 12). A recess 93 is formedin the outer periphery 98 of the nut 82. Retaining pins 99 (shown inphantom) extending axially from the body 80 into the opening 90 of body80 of trial 12 (see FIG. 12) engage in the recess 93 to restrain the nut82 within the opening 90 of the body 80.

Referring now to FIG. 16, the trial 12 is shown installed on the reamer2. It should be appreciated that the trial 12 and the reamer 2 may bedesigned such that the trial 12 and the reamer 2 directly connect toeach other. As shown in FIG. 16, a reamer trial adapter 61 may bepositioned between the reamer 2 and the trial 12. The use of a reamertrial adapter 61 permits greater flexibility in the design of the trial12 and in the design of the reamer 2, so that the reamer 2 may besuitably connected to an optimally designed driver such as driver 10 ofFIG. 5, and such that the trial 12 may be properly designed to cooperatewith reamer 2.

Referring now FIGS. 17 and 18, the reamer trial adapter 61 is shown ingreater detail. The reamer trial adapter 61 has a generally hollowcylindrical body 63. The reamer trial adapter 61 may be pinned to theproximal trial 12 by pins (not shown). A central opening 65 is formed inthe hollow body 63 and the central opening 65 is designed to receive thesecond portion of the reamer 2. A flange 67 is centrally positioned andextends outwardly from the body 63. Radial teeth 69 are positioned on asurface of the flange 67. The radial teeth 69 mate with radial teeth 71located on the trial 12. (See FIG. 16).

An end cap 73 is positioned on one end of the body 63 and defines an endcap opening 75 therein. The end cap 73 defines parallel spaced apartflats 77. Flats 77 on the adapter 61 are matingly fitted to receive theflats 38 of the shank 40 of the reamer 2 (see FIG. 4).

Another embodiment of the reamer 2 of the present invention is shown inFIG. 19 as reamer 100. The reamer 100 of FIG. 19 is similar to thereamer 2 of FIG. 6 except that the reamer 100 includes a second portion116 that is tapered. The second portion 116 may include a bayonet orJ-channel 136 similar to the bayonet or J-channel 36 of the reamer 10and may include a slot 132 similar to the slot 32 of the reamer 2 ofFIG. 6. Reamer 100 of FIG. 19 does not include the external threads asthe tapered second portion 116 may be utilized with a mating taper onthe corresponding trial to secure the trial to the reamer 100.

Referring now to FIG. 20, another embodiment of the reamer of thepresent invention is shown as reamer 200. Reamer 200 is similar toreamer 100 of FIG. 19 and includes a second portion 216 that is taperedsimilar to that of second portion 116 of the reamer 100 of FIG. 19. Thereamer 200 of FIG. 20 includes external threads 246 similar to thethreads 46 of the reamer 10. The threads 246 mate with threads (notshown) on the corresponding trial (not shown). The reamer 200 of FIG. 20may similarly use the bayonet or J-channel 236 and a slot 232 forsecurement to the corresponding driver (not shown).

Referring now to FIG. 21, another embodiment of the present invention isshown as reamer 300. The reamer 300 is utilized to provide clearance forthe tapered cylindrical periphery 81 of the body 80 of the trial 12 (seeFIG. 12). Reamer 300 includes a shank portion 316 and a cutting toothportion 314. Cutting tooth portion 314 includes a plurality of spacedapart flutes 374.

As shown in FIG. 21, the flutes 374 may have a spiral orientation. Thecutting tooth portion 314 forms an included angle θ that may be similarto the included angle θ′ formed by the tapered cylindrical periphery 81of the body 80 of the trial 12 (see FIG. 12).

The reamer 300 includes a connector 311 extending outwardly from theshank portion 314 of the reamer 300. The connector 311 is similar to theconnector 11 of the driver 10 (see FIG. 3). The reamer 300 includes acentral cavity 351 formed in the cutting tooth portion 314 of the reamer300. The central cavity 351 is sized for rotatably receiving the secondportion 16 of the reamer 2 (see FIG. 6).

After the reamer 2 has been utilized to prepare the cavity 4 in thecanal 6 and the reamer 2 is left in position in the femur 8 (see FIG.8), the reamer 300 is positioned over the reamer 2 with the centercavity 351 fitting over the second portion 16 of the reamer 2. Thereamer 300 is then rotated to remove additional material in the proximalportion of the femur 8 for permitting the receiving of the body 80 ofthe trial 12 (see FIG. 12).

Referring now to FIG. 22, reamer assembly 303 is shown. Reamer assembly303 includes the reamer 300 in position over the reamer 12.

Referring now to FIG. 23, an alternate embodiment of the presentinvention is shown as kit 400. The kit 400 includes the reamer 2 and thetrial 12. It should be appreciated that reamer 2 and the trial 12 may beseparately packaged or that the reamer 2 and the trial 12 may bepackaged together. It should also be appreciated that the kit 400 mayinclude a series of reamers and a series of trials and proximal reamers,so that all commonly used sizes are available for the surgeon.

Continuing to refer to FIG. 23, another embodiment of the presentinvention is shown as kit 500. Kit 500 includes the reamer 2, the driver10 and the trial 12. It should be appreciated that the driver 10, thereamer 2 and the trial 12 may each be individually packaged or that thetrial 12, the driver 10 and the reamer 2 may be packaged together in acommon container.

Referring now to FIG. 24, another embodiment of the present invention isshown as kit 600. Kit 600 includes the reamer 2 and the first trial 12.The kit 600 further includes a second trial 13. The second trial 13 hasat least one dimension different than that of the first trial 12. Forexample, the first trial has a calcar height B2 which is significantlyless than the calcar height B1 of the second trial 13. It should beappreciated that the reamer 2, the first trial 12 and the second trial13 may each be individually packaged or the reamer 2, the first trial 12and the second trial 13 may all be packaged in a common container.

When performing an arthroplasty, for example a total hip arthroplasty,the trial 12 is subjected to a trial reduction. In the trial reductionprocedure, the trial is positioned in the orthopaedic joint and thelimb, for example the leg, is moved about in the normal operating limitsto assure to the surgeon that the correct trial has been selected andthat the trial is properly positioned. After the trial reduction isperformed, the position of the trial 12 relative to the femur 8 isrecorded by the surgeon. The position of the implant to be positionedlater is preferably in the same corresponding location.

The surgeon may utilize any of a number of techniques to provide for theprosthesis to be in the same location to that of the trial. For example,the surgeon may merely physically note the position of the trial andcorrespondingly position the prosthesis. Alternatively, a mark orindicia may be placed on the patient to indicate the proper orientationof the prosthesis. Alternatively, instruments may be provided whichrecord the position of the trial and which instruments are utilized toproperly position the implant based on the position of the trial. Thesurgeon also use indicia in the form of witness marks on the drive shaftthat correspond with head centers.

To assist the surgeon as shown in FIG. 3, the driver 10 may includeindicia 13 formed on the driver 10. The indicia 13 may be used to assistin determining the proper depth of the distal reamer 2 during thereaming operation. The indicia 13 will preferably be used in conjunctionwith a visual line 15 with, for example, a bony landmark on the patient,for example, head centerline 17. The surgeon aligns the head centerline17 with the indicia 13 to determine the proper depth of the reamer 2.The indicia 13 may be in the form of marks or lines 19. Numbers orletters 21 may be placed adjacent the lines 19 to refer to a particulartrial or prosthesis which should be used when the line 19 corresponds tothe visualization line 15.

Referring now to FIG. 25, one such instrument is shown as alignmentdevice 700. As shown in FIG. 25, the alignment device 700 includes body720 that has a longitudinal opening 722. The longitudinal opening 722receives a rod 724 therein. The rod 724 includes a tang 766 extendingfrom an end 734 of the rod 724. The tang 766 matingly engages slot 32 ofthe reamer 2.

Arms 716 are pivotally connected to the body 720. The arms 716 includepins 718 which matingly engage openings 83 in the body 80 of the trial12. The relative position of the slot 32 to the openings 83 istransferred into the alignment device by means of the relative positionof the pins 718 to the tang 766. The relative position of the pins 718to the tang 766 may be observed by indicia 754 in the form of, forexample, lines 760 on the body 720 which are aligned with lines 756 onthe rod 724. The alignment device 700 may then later be used to orientthe proximal and distal components of the prosthesis.

Referring now to FIGS. 26, 27, 28, 29 and 30, a prosthesis 815 is shownfor use with the reamer of the present invention. The prosthesis 815includes a proximal body 817 and a distal stem 819. The proximal bodyincludes a pair of spaced apart orientation holes 821.

Referring now to FIG. 27, the proximal body 817 of the prosthesis 815includes an internal taper 823 that is matingly fitted to external taper825 of the distal stem 819.

While the internal taper 823 of the proximal body and the external taper825 of the distal stem may provide a sufficiently secure connection,referring now to FIG. 28, the prosthesis 815 may further include a nut827 which includes internal threads 829 which mate with external threads831 on the distal stem to further secure the proximal body 817 to thedistal stem 819.

Referring now to FIGS. 29 and 30, the portion of the distal stem 819adjacent proximal end 835 is shown in greater detail. As shown in FIGS.29 and 30, a recessed slot 833 is formed on the proximal end 835 of thedistal stem 819. The slot 833 has a width SW that is similar to thewidth of the slot 32 of the reamer 2 (see FIG. 4).

Referring now to FIG. 31, the alignment device 700 is shown in positionon the prosthesis 815. The alignment device 700 is positioned over aprosthesis 815 with the tang 766 of the alignment device 700 in positionengaging the slot 833 of the prosthesis 815. Similarly the pins 718 andthe arms 716 of the alignment device 700 are positioned in holes 821 inthe body 817 of the implant 815. The distal stem 819 is rotated withrespect to the proximal body 817 until the alignment mark 756 located onthe rod 724 is alignment with the mark 760 on the body 720 of thealignment device 700. When the alignment marks 756 and 760 are inalignment, the orientation of the prosthesis 815 is corresponding to thealignment of the trial 12.

It should be appreciated that since the reamer 2 is straight with acircular cross section the alignment device 700 may not be required toorient the reamer 2 to trial 12. Also, since the distal stem 819 may bestraight with a circular cross section the alignment device 700 may notbe required to orient the proximal body to distal trial 819. Orientationby sight or by marking the patient is advised to replicate orientationof the trial 12 on implant 815.

After the proximal body 817 and the distal 819 are properly aligned, theproximal body 817 needs to be securely fastened to the distal stem 819.This securement is first done providing sufficient axial force toproperly seat the distal stem 819 to the proximal body 817.

Referring now to FIG. 32, an assembly device for use in assuring thatthe proximal body and distal stem of a prosthesis for use with thereamer of the present invention may be properly secured is shown asassembly device 900. Assembly 900 includes a second member 935 in theform of a rod. The second member 935 may be, for example, threadablysecurable to distal stem 819 of the implant 815.

The assembly device may further include a first member 937 in the formof a hollow tube. The first member 937 is slidably fitted alonglongitudinal axis 939 with respect to the second member 935. The firstmember 937 may be engaged with the proximal body 817 of the implant 815.For example, opposing ends of the first member 937 and the proximal body817 may be physically mated. An arcuate slot 941 formed in the firstmember 937 may restrainably guide a pin 943 extending from the secondmember 935.

An actuating arm 945 may be secured to the end of the pin 943 and arestraining arm 947 may be secured to the first member 937. As theactuating arm 945 is rotated in the direction of arrow 949, the secondmember 935 is urged in the direction of arrow 951 with respect to thefirst member 937. Once the second member 935 is connected to the distalstem 819, the implant 815 likewise moves in the direction of arrow 951with respect to the proximal body 817, thereby properly securing thedistal stem 819 to the proximal body 817 of the implant 815.

Referring now to FIGS. 33 and 34, another embodiment of a prosthesis foruse with the reamer of the present invention is shown as implant orprosthesis 1015. The prosthesis 1015 includes a proximal body 1017 whichis secured to a distal stem 1019. Holes 1021 are formed on the proximalbody 1017 and a nut 1027 is further used to secure the distal stem 1019to the proximal body 1017. A head 1013 is attached to the proximal body1017.

The prosthesis 1015 is different than the prosthesis 815 of FIG. 26 inthat the distal stem 1019 of the prosthesis 1015 has a genuinely curvedor arcuate shape. The distal stem 1019 is utilized to extend furtherinto the medullary canal of, for example, a long bone. The medullarycanal of a long bone, particularly that of a femur, being curved orarcuate and thus the distal stem 1019 conforms to the medullary canal ofthe femur.

Referring now to FIG. 35, another embodiment of the present invention isshown as surgical procedure or method 1100. The method 1100 includes afirst step 1110 of resecting a long bone. The method 1100 furtherincludes a second step 1120 of opening a medullary canal of the longbone. The method 1100 further includes a third step 1130 of providing areamer including a surface for the removal of bone. The method 1100further includes a fourth step 1140 of attaching a driver to the reamerand a fifth step 1150 of positioning the reamer in the canal. The method1100 further includes a sixth step 1160 of reaming a cavity in the canalwith the reamer. The method 1100 further includes a seventh step 1170 ofdetaching the driver from the reamer and an eighth step 1180 ofproviding a trial. The method 1100 further includes a ninth step 1190 ofattaching the trial to the reamer and a tenth step 1194 of performing atrial reduction.

Referring now to FIGS. 36 and 37, a wrench 1200 is shown for use withthe trial 12. The wrench 1200 includes a cylindrical body 1210 and apair of cylindrical pins 1220 extending in an opposed orientation nearan end 1230 of the wrench 1200. The body 1210 may include knurls 1240 onperiphery 1250 of the wrench.

Referring now to FIGS. 15, 36 and 37, the periphery 1250 of the wrench1200 is preferably sized to slidably fit within the opening 91 of thenut 82. The pins 1220 are designed to slidably fit in the axial slots 96of the nut 82. Thus, as the wrench 1200 is rotated the nut 82 issimilarly rotated.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions, andalterations can be made therein without departing from the spirit andscope of the present invention as defined by the appended claims.

1. A kit for use with a driver in performing joint arthroplasty, saidkit comprising: a trial; and a reamer for preparing a cavity in theintramedullary canal of a long bone to assist in performing a trialreduction, the reamer including a first portion for placement at leastpartially in the cavity of the long bone and a second portion operablyconnected to the first portion, said second portion being removablyconnectable to the driver, said trial being removably attachable to saidreamer.
 2. The kit of claim 1: wherein the driver defines a longitudinalaxis thereof; wherein said reamer defines a longitudinal axis thereof,the longitudinal axis of said reamer being coincident with thelongitudinal axis of the driver when said reamer is connected to thedriver; and wherein the driver is separable and connectable to saidreamer along the longitudinal axis of the driver.
 3. The kit of claim 1:wherein said reamer includes a part thereof having a tapered externalperiphery; wherein the driver includes a part thereof having a taperedinternal periphery; and wherein said trial includes a portion thereofhaving a tapered internal periphery thereof.
 4. The kit of claim 1,further including a locking feature operably associated with at leastone of said trial and said reamer to lock at least one of the driver andsaid trial to said reamer.
 5. A kit for use in performing hip jointarthroplasty, said kit to be utilized to prepare a cavity in the femoralcanal of a femur with the use of a driver and to assist in performing atrial reduction, said kit comprising: a hip femoral component trial; anda reamer for preparation of the cavity in the femoral canal, said reamerincluding a first portion for placement at least partially in the cavityof the femur and a second portion connectable to the driver, said trialand the driver being removably attachable to said reamer, so that thesaid reamer and the driver can be assembled to prepare the cavity and sothat said reamer and said trial can be assembled to form a hip femoralcomponent trial assembly without the removal of said reamer from thecavity.
 6. The kit of claim 5: wherein said reamer includes a partthereof having a tapered external periphery; wherein the driver includesa part thereof having a tapered internal periphery; and wherein saidtrial includes a portion thereof having a tapered internal peripherythereof.
 7. The kit of claim 5, further comprising a second trial havingat least one dimension different than said first mentioned trial, saidsecond trial being removeably attachable to said reamer.
 8. The kit ofclaim 5, further including a locking feature operably associated with atleast one of said reamer and said trial to lock at least one of thedriver and said trial to said reamer.
 9. The kit of claim 5: wherein atleast one of said reamer and the driver includes a pin extendingtherefrom; and wherein the other of said reamer and the driver defines avoid for receiving said pin, said pin and the void cooperating to locksaid reamer to the driver.
 10. The kit of claim 1, wherein said trialand said reamer are packaged in a common container.
 11. A reamer forpreparing a cavity in the intramedullary canal of a long bone with theuse of a driver and for cooperation with an implant trial to assist inperforming a trial reduction, said reamer comprising: a first portionfor preparation of the cavity in the canal, the first portion adaptedfor placement at least partially in the cavity of the long bone; and asecond portion operably connected to the first portion, said secondportion connectable to the driver to rotate said reamer, said reamerbeing removably attachable to the trial and to the driver.
 12. Thereamer of claim 11: wherein the first portion defines a longitudinalaxis thereof; wherein the second portion defines a longitudinal axisthereof, the longitudinal axis of the second portion being coincidentwith the longitudinal axis of the first portion; and wherein said reameris separable and connectable to the driver and the trial along thelongitudinal axis of said first portion.
 13. The reamer of claim 11,wherein said reamer includes a portion thereof having a tapered externalperiphery.
 14. The reamer of claim 11, further including a lockingfeature adapted to lock the trial and the driver to said reamer.
 15. Thereamer of claim 12: wherein said long bone comprises a femur; andwherein said implant trial comprises a hip femoral implant trial.
 16. Amethod for providing joint arthroplasty comprising: resecting a longbone; opening a medullary canal of the long bone; providing a reamerincluding a surface for the removal of bone; attaching a driver to thereamer; positioning the reamer in the canal; reaming a cavity in thecanal with the reamer; detaching the driver from the reamer; providing atrial; attaching the trial to the reamer; and performing a trialreduction.
 17. The method of claim 16 further comprising the steps of:removing the reamer and the trial; providing a joint prosthesis; andimplanting the joint prosthesis in the cavity
 18. The method of claim16: wherein the providing the reamer step comprises providing a reamerwith the reamer having an externally tapered shaft; wherein theattaching the driver step comprises attaching a driver having aninternally tapered shaft to the externally tapered shaft of the reamer;and wherein the providing the trial step comprises providing a trialhaving an internally tapered shaft fitted to the externally taperedshaft of the reamer.
 19. The method of claim 16, wherein the long bone afemur.
 20. A driver for use with a reamer to prepare a cavity in theintramedullary canal of a long bone, said driver including indiciathereon corresponding to at least one of a bony landmark on a patientand a portion of a trial or an implant.